JP2014226947A - On-vehicle sensor and on-vehicle sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle sensor which does not require that an identifier is preliminarily assigned.SOLUTION: An on-vehicle sensor 1 which is mounted on a vehicle VE and is connected to a communication bus CAN constructed on the vehicle VE includes: a bus connection connector 40 which comprises communication external terminals T3, T4 and one or a plurality of setting external terminals T5, T6 turned into either connection state of such a first connection state so as not to be connected to any potential and of such a second connection state that none of the terminals are connected to ground potential GND and is used for connection to the communication bus CAN; discrimination parts S1 to S4, S5 to S7 for discriminating that the connection state is either of the first connection state and the second connection state with respect to each of one or the plurality of setting external terminals T5, T6; and an identifier setting part S8 for setting an identifier ID of the on-vehicle sensor 1 used on the communication bus CAN according to the connection state of one or the plurality of setting external terminals T5, T6 which are discriminated.

Description

  The present invention relates to an in-vehicle sensor mounted on a vehicle and connected to a communication bus constructed in the vehicle, and an in-vehicle sensor system in which a plurality of in-vehicle sensors are connected to a communication bus.

Various sensors such as a gas sensor such as an oxygen sensor and a NOx sensor, a temperature sensor, and a knock sensor are mounted on the vehicle. Such an in-vehicle sensor is connected to a communication bus built in the vehicle, and centralized control is performed by an ECU (electronic control unit) connected to the communication bus. For this reason, each vehicle-mounted sensor is assigned an identifier used to identify each on the communication bus. By designating this identifier, the ECU can communicate with each vehicle-mounted sensor via the communication bus. To exchange communication data.
Such communication bus standards include CAN (Controller Area Network) and LIN (Local Interconnect Network).

JP 2007-24566 A JP 2007-309905 A

  For this reason, each in-vehicle sensor needs to be installed at a predetermined location in the vehicle with an identifier used in a communication bus assigned in advance. The same thing may be used several times. For example, as shown in FIG. 6 of Patent Document 1, in a fuel cell vehicle, a plurality of the same hydrogen sensors are mounted as in-vehicle sensors. As for the details of the hydrogen sensor, Patent Document 2 discloses a hydrogen sensor (hydrogen gas leak detector) installed in the piping of a fuel cell unit of an automobile. For this reason, it is necessary to prepare an in-vehicle sensor in which only the identifier is changed corresponding to the installation location even though they are of the same type. Further, when installing a plurality of in-vehicle sensors in a vehicle, it takes a lot of time to manage these in order to prevent misplacement in which sensors with different identifiers are connected due to the mixed use of in-vehicle sensors.

  The present invention has been made in view of such problems, and includes an in-vehicle sensor that does not need to be assigned an identifier in advance, and an in-vehicle sensor system in which a plurality of such in-vehicle sensors are connected to a communication bus. The purpose is to provide.

  One aspect thereof is an in-vehicle sensor mounted on a vehicle and connected to a communication bus built in the vehicle, and one or more communication external terminals connected to a communication line through which communication data flows in the communication bus In addition, each connection state is either a first connection state that is not connected to any potential outside the in-vehicle sensor, or a second connection state that is connected to the ground potential outside the in-vehicle sensor. For each of the bus connection connector used for connection to the communication bus and the one or more setting external terminals, the connection state is the first connection state and the one or more setting external terminals. The identifier of the in-vehicle sensor used in the communication bus is determined according to the determination state of the second connection state and the connection state of the determined one or more setting external terminals. An identifier setting unit for constant, an in-vehicle sensor comprising a.

In this in-vehicle sensor, the bus connection connector is provided with one or a plurality of setting external terminals. Each of the setting external terminals has a first connection state (open state) that is not connected to any potential outside the vehicle-mounted sensor, and a second connection state (grounding) that is connected to the ground potential outside the vehicle-mounted sensor. State).
And this vehicle-mounted sensor discriminate | determines by the discrimination | determination part whether the connection state is the 1st connection state (open state) or the 2nd connection state (grounding state) about each of the external terminal for setting, and 1 Alternatively, an identifier used in the communication bus is set according to the connection state of a plurality of setting external terminals.
For this reason, there is no need to assign an identifier to the in-vehicle sensor in advance, and when connecting to a communication bus using a bus connection connector and installing in a vehicle, an external terminal for setting the bus connection connector is installed at each installation location. By setting the connection state corresponding to, an identifier can be set and a plurality of in-vehicle sensors of the same type can be used.

The identifier used on the communication bus is, for example, an 11-bit code when the communication bus is CAN. When the communication bus is LIN, it is a 6-bit code. On the other hand, since the setting external terminal can be set in two ways of the first connection state (open state) and the second connection state (ground state) for each terminal, when n setting external terminals are provided, 2 ⁿ kinds of identifiers can be set. Therefore, for example, when two setting external terminals are provided, 2 ² = 4 identifiers can be set.

  Moreover, in this in-vehicle sensor, the setting external terminal is either in an open state (first connection state) or connected to a ground potential (second connection state), and is externally (mounted on the vehicle). Is not connected to a power supply potential supplied from the battery or other potential generated outside the vehicle-mounted sensor from this power supply potential. For this reason, it is difficult for noise due to a surge voltage to be superimposed on an external power supply potential or other potentials on the setting external terminal. As a result, erroneous determination due to noise is less likely to occur, and the connection state of the setting external terminal can be appropriately determined to set the identifier correctly.

  Further, the vehicle-mounted sensor includes a microprocessor having an input signal port to which an input signal is input, and the determination unit is connected to the setting external terminal and the input signal port, and the setting external terminal The level generation circuit for generating the input signals having different voltage levels according to the connection state of the input signal, and the connection state of the setting external terminal according to the voltage level of the input signal input to the input signal port However, it is preferable that the vehicle-mounted sensor includes a level determination unit that determines whether the connection state is the first connection state or the second connection state.

In this in-vehicle sensor, the level generation circuit of the discriminating unit generates input signals having different voltage levels according to the difference in the connection state of whether the setting external terminal is in the first connection state or the second connection state. The signal is input to the input signal port of the microprocessor. Among the determination units, the level determination unit in the microprocessor determines whether the connection state of the setting external terminal is the first connection state or the second connection state depending on the voltage level of the input signal input to the input signal port. Determine if it exists.
Thus, the connection state of the setting external terminal can be easily determined based on the voltage level of the input signal input to the input signal port of the microprocessor.
Examples of the input signal port include a digital input signal port (I / O input port) or an analog input signal port (A / D input port). For example, when a digital input signal port (I / O input port) is used, the voltage level of the input signal generated by the level generation circuit is set to a high level and a low level according to the connection state of the setting external terminal. Two different voltage levels that can be recognized as levels may be used. Such an input signal may be input to an analog input signal port (A / D input port). On the other hand, when the A / D input port is used, the voltage level of the input signal generated by the level generation circuit can be set to two voltage levels that can be distinguished from each other within a range where A / D input is possible.

  Further, the vehicle-mounted sensor includes a potential generation unit that generates a constant determination potential, and the level generation circuit connects the setting external terminal to the determination potential via a resistor, A vehicle-mounted sensor that is a circuit that generates the input signal using the potential of the setting external terminal may be used.

  In this in-vehicle sensor, the level generation circuit connects the setting external terminal to a certain determination potential via a resistor. For this reason, the potential of the setting external terminal is not indefinite even if the connection state of the setting external terminal is the first connection state (open state), and is the first connection state or the second connection state? The potential of the setting external terminal is determined in accordance with the connection state. As a result, the level generation circuit can generate an appropriate input signal using the determined potential of the external terminal for setting, and thus the connection state can be appropriately determined using the input signal.

The discrimination potential used includes, for example, a control power source potential used as a power source for a microprocessor, in addition to a potential generated by a circuit dedicated to the discrimination potential used in the level generation circuit. In this case, the stabilized power supply circuit that generates the control power supply potential from the battery potential serves as the potential generation unit.
Further, for example, an output potential of a surge protection circuit for absorbing a surge voltage superimposed on the battery potential can be mentioned. In this case, the surge protection circuit becomes the potential generation unit. When using a potential whose discrimination potential is higher than the control power supply potential, such as this output potential, when the input signal is generated by the level generation circuit, the input signal is reduced by using a transistor or a level conversion IC. A circuit having a voltage level that can be input to the input signal port of the processor is preferable.
It is also possible to output a high level or a predetermined potential from a digital or analog output signal port (I / O output port, D / A output port) of the microprocessor and use this output signal as a discrimination potential. In this case, the output signal port is a potential generation unit.

  Further, the vehicle-mounted sensor includes a microprocessor having an input signal port for inputting an input signal and an output signal port for outputting an output signal, and the determination unit includes the setting external terminal and the input signal port. And the first input signal that is the input signal when the connection state of the external terminal for setting is the first connection state, and the connection state is the second connection state. At least one of the second input signals, which are the input signals at a certain time, changes according to a change in the output signal, and the first input signal and the second input signal are different from each other. An input generation circuit for generating the output signal, an output changing unit for changing the output signal output from the output signal port, and the input signal port for the change of the output signal. It is preferable that the vehicle-mounted sensor includes a response determination unit that determines whether the connection state of the setting external terminal is the first connection state or the second connection state using the response of the input signal. .

In this in-vehicle sensor, the input generation circuit of the discriminating unit uses input signals (first signals) that have different responses to changes in the output signal depending on whether the connection state of the setting external terminal is the first connection state or the second connection state. 1 input signal and second input signal) are generated and input to the input signal port of the microprocessor. The output signal output from the output signal port is changed by the output changing unit in the microprocessor, and the input signal input to the input signal port corresponding to the change in the output signal by the response determining unit in the microprocessor. Is used to determine whether the connection state of the setting external terminal is the first connection state or the second connection state.
Thus, the connection state of the setting external terminal can be appropriately determined based on the response of the input signal input to the input signal port to the change in the output signal output from the output signal port of the microprocessor.

Examples of the output signal port include a digital output signal port (I / O output port) or an analog output signal port (D / A output port). When a digital output signal port (I / O output port) is used, the output changing unit changes the output signal between a high level and a low level. When an analog output signal port (D / A output port) is used, the output changing unit can change the output signal to an arbitrary potential within a range where D / A output is possible. In addition, as the input signal port, a digital input signal port (I / O input port) or an analog input signal port (A / D input port) can be cited as described above.
As for the relationship between the combination of the connection state of the output signal and the setting external terminal and the input signal corresponding to this, for example, when the output signal is temporally changed, the input signal is output in one connection state. There is a relationship in which the input signal changes in synchronization with the signal while the input signal does not change regardless of the output signal in the other connection state. In addition, there may be cases in which the time constant of the response of the input signal to the change of the output signal has a different relationship depending on the connection state.

  Furthermore, in any one of the above-described in-vehicle sensors, the input generation circuit is a circuit that connects the input signal port to the setting external terminal and to the output signal port via a resistor. A vehicle-mounted sensor is recommended.

In this in-vehicle sensor, since the above-described circuit is used as an input generation circuit, for example, when a digital output signal port (I / O output port) is used as an output signal port, an external terminal for setting is used. When the connection state is the first connection state (open state), the input signal changes in the same manner as the output signal. That is, when the output signal is set to a high level, the input signal is also set to a high level, and when the output signal is set to a low level, the input signal is also set to a low level. On the other hand, when the connection state is the second connection state (grounding state), the input signal is at a low level regardless of whether the output signal is at a high level or a low level. That is, when the input signal changes in synchronization with changes in the high level and low level of the output signal, the connection state is the first connection state (open state). On the other hand, when the input signal does not change even if the output signal changes and is maintained at the low level, the connection state is the second connection state (ground state).
In this in-vehicle sensor, it is possible to easily determine the connection state of the setting external terminal with an input generation circuit having a simple configuration.
As the output signal port, an analog output signal port (D / A output port) may be used instead of the digital output signal port (I / O output port) described above. As an input signal port for inputting an input signal, either a digital input signal port (I / O input port) or an analog input signal port (A / D input port) is selected according to the voltage level of the output signal. It may be used.

  Another aspect is an in-vehicle sensor system having a plurality of any of the above-described in-vehicle sensors and the communication bus to which these are connected, and for each of the plurality of in-vehicle sensors, the bus of the in-vehicle sensor. A plurality of connection paths for connecting the in-vehicle sensor to the communication bus, the plurality of connection paths including the one or more communication external terminals of the bus connection connector. The communication connection path connected to the communication line in the communication bus and the setting external terminal of the bus connection connector are not connected to any potential or connected to the ground potential, and the setting external terminal One or a plurality of setting paths that define the connection state of the first connection state or the second connection state as one or more of the setting paths. The connection status or a combination of the set external terminal specified is different from each other between the connecting passage, all of the vehicle sensor, a vehicle sensor system comprising at different the identifier to each other.

  This in-vehicle sensor system includes a connection path including a sensor connection connector that fits into a bus connection connector of the in-vehicle sensor. Of these connection paths, the setting path that determines the connection state of the setting external terminal of the bus connection connector as either the first connection state or the second connection state is the connection state of the setting external terminal determined by itself or its The combination differs between the connection paths. Thereby, it is not necessary to assign an identifier in advance, and an in-vehicle sensor system that can use a plurality of in-vehicle sensors of the same type by setting different identifiers for each in-vehicle sensor.

It is explanatory drawing which shows schematic structure of the vehicle-mounted sensor which concerns on Embodiment 1. FIG. 1 is a schematic diagram of an in-vehicle sensor system in which a plurality of in-vehicle sensors according to Embodiments 1 and 2 are connected to a communication bus. It is a flowchart which shows the operation | movement at the time of the identification ID setting of a microprocessor among the vehicle-mounted sensors which concern on Embodiment 1. FIG. It is explanatory drawing which shows the structure of the level generation circuit of the modification 1. It is explanatory drawing which shows the structure of the level generation circuit of the modification 2. It is explanatory drawing which shows schematic structure of the vehicle-mounted sensor which concerns on Embodiment 2. FIG. It is a flowchart which shows the first half part of the operation | movement at the time of the identification ID setting of a microprocessor among the vehicle-mounted sensors which concern on Embodiment 2. FIG. It is a flowchart which shows the second half part of the operation | movement at the time of the identification ID setting of a microprocessor among the vehicle-mounted sensors which concern on Embodiment 2. FIG. It is explanatory drawing which shows the structure of the input generation circuit of the modification 3.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of an in-vehicle sensor 1 according to the first embodiment mounted on a vehicle VE. FIG. 2 is a schematic diagram of an in-vehicle sensor system 2 in which a plurality of in-vehicle sensors 1 are connected to an ECU via a communication bus constructed in the vehicle VE. In this in-vehicle sensor system 2, a CAN bus is used as a communication bus. The in-vehicle sensor 1 is obtained by applying the present invention to the hydrogen sensor disclosed in Patent Document 1. However, in this Embodiment 1, description about the sensor part of the vehicle-mounted sensor 1 is abbreviate | omitted, and only the part in connection with communication with CAN bus which is a communication bus, and ECU is demonstrated.

As shown in FIG. 1, the plurality (four in the first embodiment) of in-vehicle sensors 1 and 1 mainly include a microprocessor 10 having a CAN controller function, a CAN transceiver 50, a surge protection circuit 20, and a stabilization. A power supply circuit 30 and a bus connection connector 40 having six terminals T1 to T6 are provided. These in-vehicle sensors 1 are connected to the CAN bus by connection paths 100, 200, 300, and 400 including sensor connection connectors 110, 210, 310, and 410 that are respectively fitted to the bus connection connector 40 (also in FIG. 2). reference).
The CAN bus includes two communication lines CANH and CANL through which communication data flows, a VSUP line connected to the power supply potential VB supplied from the + terminal of the battery BT (12V specification) of the vehicle VE, and the battery BT. A COM line connected to the ground potential GND connected to the terminal; Communication on the CAN bus is differential serial communication that transmits a signal with a potential difference between the two communication lines CANH and CANL.

First, the connection paths 100, 200, 300, and 400 will be described.
In addition to the sensor connection connectors 110, 210, 310, and 410, the connection paths 100 to 400 connect the terminals T1 and T2 of the bus connection connector 40 fitted to the sensor connection connectors 110 to 410 to the VSUP line and the COM line of the CAN bus, respectively. And a communication connection path 130 including lines 131 and 132 for connecting the terminals T3 and T4 of the bus connection connector 40 to the communication lines CANH and CANL, respectively.
Furthermore, the connection paths 100 to 400 include setting paths 140 (lines 141 and 142), 240, 340, and 440 that determine the connection state of the terminals T5 and T6 of the bus connection connector 40 outside the in-vehicle sensor 1.
In FIG. 1, the line 141 indicated by a solid line in the setting path 140 is connected to the COM line of the CAN bus, whereby the terminal T5 of the bus connection connector 40 connected to the connection path 100 is an in-vehicle sensor. 1 is connected to the ground potential GND outside (a second connection state). Further, the line 142 indicated by a broken line does not actually exist and is not connected to the COM line. Thereby, the terminal T6 of the bus connection connector 40 connected to the connection path 100 is in an open state in which it is not connected to any potential outside the in-vehicle sensor 1 (first connection state). That is, the setting path 140 of the connection path 100 is determined to be a combination in which the terminal T5 is connected to the ground potential GND and the terminal T6 is opened.

The connection paths 200, 300, and 400 have setting paths 240, 340, and 440, respectively, instead of the setting path 140 of the connection path 100. Although not shown, the setting path 240 is determined so as to be a combination in which the terminals T5 and T6 are both connected to the ground potential GND. Further, the setting path 340 is determined so that the terminal T5 is in an open state and the terminal T6 is connected to the ground potential GND. Further, the setting path 440 is determined to be a combination in which both the terminals T5 and T6 are opened.
As described above, the setting paths 140, 240, 340, and 440 have different combinations of the connection states of the terminals T5 and T6 that are defined by the setting paths 140, 240, 340, and 440, respectively. Of the connection paths 100 to 400, the sensor connection connectors 110 to 410 have the same connector specifications except that different setting paths 140 to 440 are connected to each other. Further, the power lines 120 and the communication connection paths 130 other than the setting paths 140 to 440 and the sensor connection connectors 110 to 410 are all common to the connection paths 100 to 400.

Next, the internal configuration of the in-vehicle sensor 1 will be described.
As described above, the terminal T1 of the bus connection connector 40 is connected to the VSUP line of the CAN bus through the line 121 of the power supply line 120 among the connection paths 100 to 400. That is, the terminal T1 is a power supply terminal connected to the power supply potential VB. Further, as described above, the terminal T2 is connected to the COM line of the CAN bus through the line 122 of the power supply line 120 among the connection paths 100 to 400. That is, the terminal T2 is a ground terminal connected to the ground potential GND.
The power supply potential VB supplied to the terminal T1 is connected to a surge protection circuit 20 composed of a varistor or the like that absorbs a surge voltage superimposed on the power supply potential VB. The output potential VB1 of the surge protection circuit 20 Therefore, the stabilized power supply voltages Vcc1 (= + 5 V) and Vcc2 (= + 3.3 V) used inside the in-vehicle sensor 1 are generated by the stabilized power supply circuit 30. The Vcc terminal of the microprocessor 10 is connected to the control power supply voltage Vcc2 (= + 3.3 V), and the microprocessor 10 is driven by this control power supply voltage Vcc2. Further, the CAN transceiver 50 is driven by two power supplies, namely, a control power supply voltage Vcc1 (= + 5V) connected to the Vcc terminal and a control power supply voltage Vcc2 (= + 3.3V) connected to the Vio terminal. .

  Terminals T3 and T4 of the bus connection connector 40 are connected to the CAN bus communication lines CANH and CANL through the communication connection path 130 (lines 131 and 132) of the connection paths 100 to 400 outside the in-vehicle sensor 1. It is an external terminal and is connected to the CAN transceiver 50 inside the in-vehicle sensor 1. The CAN transceiver 50 is connected to serial communication ports TxD and RxD of the microprocessor 10 which is a CAN controller. The in-vehicle sensor 1 exchanges communication data with the ECU via the CAN bus through the communication connection path 130 connected to the terminals T3 and T4 of the bus connection connector 40 and the communication lines CANH and CANL. The ECU designates a device connected to the CAN bus by an identifier (hereinafter referred to as an identification ID), and performs communication with each device. For this reason, it is necessary to assign each vehicle-mounted sensor 1 an identification ID that does not overlap on the CAN bus.

Terminals T5 and T6 of the bus connection connector 40 are connected to any potential outside the in-vehicle sensor 1 by the setting paths 140 to 440 of the connection paths 100 to 400, respectively, and This is an external terminal for setting that is brought into one of the second connection states (ground state) connected to the ground potential GND outside the in-vehicle sensor 1. As described above, in FIG. 1, the terminal T5 is connected to the ground potential GND by the setting path 140 (the line 141 indicated by the solid line and the nonexistent line 142 indicated by the broken line) of the connection path 100 (first line). 2 connection state), the terminal T6 is open (first connection state).
These two terminals T5 and T6 are connected to the cathode side of diodes D1 and D2 for protection against surge noise, etc., and the anode side of these diodes D1 and D2 is controlled via resistors R1 and R2, respectively. Power supply Vcc2 (= + 3.3V) is connected. That is, the terminals T5 and T6 are connected to the control power supply Vcc2 via the protection diodes D1 and D2 and the resistors R1 and R2, respectively. The resistors R1 and R2 have one end connected to the control power supply Vcc2, while the other ends of the diodes D1 and D2 are connected to the digital input signal port (I / O input port) of the microprocessor 10, respectively. ) Are input ports 10I1 and 10I2. In the first embodiment, the potential (+3.3 V) of the control power supply voltage Vcc2 corresponds to the determination potential, and the stabilized power supply circuit 30 corresponds to the potential generation unit. Further, level generation circuits 60 and 61 connected to the terminals T5 and T6 and the input ports 10I1 and 10I2 of the microprocessor 10 are constituted by the diodes D1 and D2 and the resistors R1 and R2.
Thus, when the terminals T5 and T6 are in the open state (first connection state), the voltage levels of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 are always the control power supply voltage Vcc2 (= + 3. 3), the microprocessor 10 recognizes this as a high level. On the other hand, when the terminals T5 and T6 are connected to the ground potential GND (second connection state), the voltage levels of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 are always set to the ground potential GND. The voltage is about 0.7 V, which is higher by the forward voltage of the diodes D1 and D2, and the microprocessor 10 recognizes this as a low level.

  Therefore, the microprocessor 10 determines whether the connection state of each of the terminals T5 and T6 is an open state (first connection state) or a ground state (second connection state). Is determined based on the voltage level of the input signals SI1 and SI2, that is, the input level of the high level or the low level. Specifically, for example, when the input level of the input port 10I1 is high, it is determined that the terminal T5 connected to the input port 10I1 is in an open state (first connection state), and the input port 10I1 When the input level is low, it is determined that the terminal T5 connected to the input port 10I1 is connected to the ground potential GND (second connection state) (input determination unit). The same applies to the terminal T6 connected to the input port 10I2.

In FIG. 1, the microprocessor 10 determines that the terminal T5 is connected to the ground potential GND (second connection state) because the input level of the input port 10I1 is low. Further, since the input level of the input port 10I2 becomes high level, it is determined that the terminal T6 is in an open state (first connection state).
Then, the identification ID of the in-vehicle sensor 1 is set according to the determined connection state of the terminals T5 and T6 (identifier setting unit). Specifically, the identification ID is set to a code corresponding to the connection state. In the first embodiment, since there are two terminals T5 and T6 as setting external terminals, there are 2 ² = 4 combinations depending on the connection state of the two terminals T5 and T6, and there are four types of identification. An ID can be set.
The identification ID may be set once at a predetermined timing such as when the vehicle VE is activated and the power of the microprocessor 10 is turned on. The microprocessor 10 stores the identification ID set in this way, and responds to the ECU when the stored identification ID matches the identification ID specified by the ECU.

Next, the operation at the time of setting the identification ID of the microprocessor 10 in the in-vehicle sensor 1 according to the first embodiment will be described with reference to the flowchart of FIG. The microprocessor 10 executes the operation for setting the identification ID only once after the power is turned on.
First, in step S1, the input levels of the two input ports 10I1, 10I2 (input signals SI1, SI2) of the microprocessor 10 are read.

  Next, in step S2, it is determined whether or not the input level of the input port 10I1 read in step S1 is a high level. If the input level of the input port 10I1 is high, the determination is YES in step S2, the process proceeds to step S3, and it is determined that the terminal T5 connected to the input port 10I1 is in an open state (first connection state). Then, the process proceeds to step S5. On the other hand, when the input level of the input port 10I1 is low level, No is made in step S2, the process proceeds to step S4, and the terminal T5 connected to the input port 10I1 is connected to the ground potential GND (first). 2), the process proceeds to step S5.

  In step S5, it is determined whether or not the input level of the input port 10I2 read in step S1 is a high level. If the input level of the input port 10I2 is high, the determination is YES in step S5, the process proceeds to step S6, and it is determined that the terminal T6 connected to the input port 10I2 is in an open state (first connection state). Then, the process proceeds to step S8. On the other hand, when the input level of the input port 10I2 is low level, No is made in step S5, the process proceeds to step S7, and the terminal T6 connected to the input port 10I2 is connected to the ground potential GND (first). 2), the process proceeds to step S8.

In step S8, the identification ID of the in-vehicle sensor 1 is set to a code corresponding to the connection state of the two terminals T5 and T6, the set identification ID is stored in the memory, and the operation for setting the identification ID is completed.
In the first embodiment, the microprocessor 10 executing steps S1 to S4 and steps S5 to S7 corresponds to a level determination unit, and the level determination unit and level generation circuits 60 and 61 correspond to a determination unit. To do. Further, the microprocessor 10 executing step S8 corresponds to an identifier setting unit.

  Next, the in-vehicle sensor system 2 shown in FIG. 2 will be described. In this in-vehicle sensor system 2, four in-vehicle sensors 1 of the same specification according to the first embodiment are connected to a CAN bus using four connection paths 100, 200, 300, and 400. As described above, the four connection paths 100, 200, 300, and 400 have the same connector specifications for the sensor connection connectors 110 to 410, and the power supply line 120 and the communication connection path 130 are all common. The combinations of the connection states of the setting paths 140, 240, 340, and 440 that define the connection states of the terminals T5 and T6 of the in-vehicle sensors 1 are different from each other. Thereby, in this vehicle-mounted sensor system 2, the connection state of terminal T5, T6 of each vehicle-mounted sensor 1 is made into a mutually different state, and four types of identification ID are set.

As described above, in the vehicle-mounted sensor 1 according to the first embodiment, the bus connection connector 40 is provided with the terminals T5 and T6 (setting external terminals) for setting the identification ID (identifier). Terminals T5 and T6 are each in a first connection state (open state) that is not connected to any potential outside the in-vehicle sensor 1, and in a second connection state that is connected to the ground potential GND outside the in-vehicle sensor 1. One of the connection states (ground state) is set.
The in-vehicle sensor 1 determines whether the connection state of each of the terminals T5 and T6 is the first connection state (open state) or the second connection state (ground state). Discrimination is performed based on the input levels of the input signals SI1 and SI2 input to 10I1 and 10I2 (level discrimination unit: steps S1 to S4 and steps S5 to S7), and this connection state is supported by the determined connection status of the terminals T5 and T6. The identification ID used in the CAN bus (communication bus) is set in the code (identifier setting unit: step S8).
For this reason, it is not necessary to assign an identification ID to the in-vehicle sensor 1 in advance, and when connecting to the CAN bus using the bus connection connector 40 and installing in the vehicle, the terminal T5 of the bus connection connector 40 at each installation location. By setting T6 to a connection state corresponding to the installation location, an identification ID can be set and a plurality of in-vehicle sensors 1 of the same type can be used.
Moreover, in this in-vehicle sensor 1, the terminals T5 and T6 are either in an open state (first connection state) or connected to the ground potential GND (second connection state), and are external (vehicles). The power supply potential VB supplied from the battery BT mounted on the VE, the power supply potential VB, and other potentials generated outside the vehicle-mounted sensor 1 are not connected. For this reason, it is difficult for noise caused by a surge voltage to be superimposed on the external power supply potential VB and other potentials at the terminals T5 and T6. As a result, erroneous discrimination due to noise is unlikely to occur, and the connection state of the terminals T5 and T6 can be appropriately determined and the identification ID can be set correctly.

Furthermore, in the in-vehicle sensor 1 of the first embodiment, the level generation circuits 60 and 61 connect the terminal T5 and T6 in the first connection state (open state) or the second connection state (ground state). In response to the difference, input signals SI1 and SI2 that are high level or low level are generated and input to the input ports 10I1 and 10I2 of the microprocessor 10. In addition, the level determination unit (steps S1 to S4 and steps S5 to S7) in the microprocessor 10 is connected to the input ports 10I1 and 10I2 depending on the input levels of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2. It is determined whether the terminals T5 and T6 are in the first connection state (open state) or the second connection state (ground state).
Thereby, the connection state of the terminals T5 and T6 can be appropriately determined based on the input levels of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 of the microprocessor 10.

  Furthermore, in the in-vehicle sensor 1 of the first embodiment, the level generation circuits 60 and 61 connect the terminals T5 and T6 to the control power supply voltage Vcc2 (discrimination potential) via the resistors R1 and R2. For this reason, the potentials of the terminals T5 and T6 are not indefinite even if the connection state of the terminals T5 and T6 is the first connection state (open state), and whether the potential is the first connection state (open state) or the second connection. The potentials of the terminals T5 and T6 are determined according to the connection state of the state (ground state). As a result, the level generation circuits 60 and 61 can generate appropriate input signals SI1 and SI2 using the determined potentials of the terminals T5 and T6. Therefore, the connection state is established using the input signals SI1 and SI2. Can be properly determined.

  Further, in the in-vehicle sensor system 2 in which a plurality (four) of the in-vehicle sensors 1 according to the first embodiment are connected, the connection paths 100, 200, and 300 including the sensor connection connector 110 fitted to the bus connection connector 40 of the in-vehicle sensor 1. , 400. Of the connection paths 100 and the like, the setting paths 140 and 240 determine the connection state of the terminals T5 and T6 of the bus connection connector 40 as either the first connection state (open state) or the second connection state (ground state). , 340, and 440 have different combinations of the connection states of the terminals T5 and T6 determined by themselves among the connection paths 100 to 400. Accordingly, different identification IDs can be set for the four in-vehicle sensors 1 simply by connecting the bus connection connectors 40 of the four in-vehicle sensors 1 to the sensor connection connectors 110 to 410 of the connection paths 100 to 400, respectively. Thus, there is no need to assign an identification ID in advance, and there is an in-vehicle sensor system 2 that can use a plurality of in-vehicle sensors 1 of the same product type and specifications by setting the identification ID of each in-vehicle sensor 1 differently. can get.

(Deformation 1, 2)
Next, a modified embodiment in which the configuration of the level generation circuits 60 and 61 of the first embodiment is changed will be described with reference to FIGS.
In the vehicle-mounted sensor 1 according to the first embodiment, the terminals T5 and T6 are connected to the control power supply voltage Vcc2 via the protection diodes D1 and D2 and the resistors R1 and R2, respectively, and the anodes of the diodes D1 and D2 The sides were connected to the input ports 10I1 and 10I2 of the microprocessor 10, respectively. The diodes D1 and D2 and the resistors R1 and R2 constitute level generation circuits 60 and 61 connected to the terminals T5 and T6 and the input ports 10I1 and 10I2 of the microprocessor 10, respectively.

  On the other hand, in the first modification shown in FIG. 4, the terminals T5 and T6 are connected to the bases of the transistors Q1 and Q2, respectively, and to the cathode side of the protective diodes D3 and D4. The anodes of the diodes D3 and D4 are connected to the control power supply voltage Vcc2 (= + 3.3V) via resistors R3 and R4, respectively. That is, the terminals T5 and T6 are connected to the control power supply voltage Vcc2 via protective diodes D3 and D4 and resistors R3 and R4, respectively. The emitters of the transistors Q1 and Q2 are grounded to the ground potential GND, and the collectors of the transistors Q1 and Q2 are connected to the control power supply voltage Vcc2 via the resistors R5 and R6. 10I1 and 10I2 are connected. The diodes D3 and D4, resistors R3 and R4, transistors Q1 and Q2, and resistors R5 and R6 constitute level generation circuits 70 and 71. In the first modification, as in the first embodiment, the potential (+3.3 V) of the control power supply voltage Vcc2 corresponds to a determination potential, and the stabilized power supply circuit 30 corresponds to a potential generation unit.

  Thus, when the terminals T5 and T6 are opened (first connection state), the level generation circuits 70 and 71 control the bases of the transistors Q1 and Q2 via the diodes D3 and D4 and the resistors R3 and R4. Since the transistors Q1 and Q2 are turned on, the input levels of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 connected to the collectors of the transistors Q1 and Q2 ) Is always low. On the other hand, when the terminals T5 and T6 are connected to the ground potential GND (second connection state), since the bases of the transistors Q1 and Q2 are connected to the ground potential GND, the transistors Q1 and Q2 are turned off, and the resistor The input levels (voltage levels) of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 connected to the control power supply voltage Vcc2 via R5 and R6 are always high.

  Therefore, when the input level of the input port 10I1 is low, the microprocessor 10 determines that the terminal T5 connected to the input port 10I1 is in an open state (first connection state), and the input port 10I1. When the input level is high, it is determined that the terminal T5 connected to the input port 10I1 is connected to the ground potential GND (second connection state). The same applies to the terminal T6 connected to the input port 10I2. That is, in the level generation circuits 70 and 71 of the first modification, the relationship between the connection state and the input level of the input ports 10I1 and 10I2 corresponding to the connection state is the level generation circuits 60 and 61 of the first embodiment. However, as in the first embodiment, the connection state of the terminals T5 and T6 can be determined by the input levels of the input ports 10I1 and 10I2.

  Therefore, even when the level generation circuits 70 and 71 of the first modification are used in place of the level generation circuits 60 and 61 of the first embodiment, the in-vehicle sensor 1 does not need to be assigned an identification ID in advance, and is connected to the bus. By setting the terminals T5 and T6 of the connector 40 to the connection state corresponding to the installation location, a plurality of in-vehicle sensors 1 of the same product type can be used by setting the identification ID. Further, since the terminals T5 and T6 of the in-vehicle sensor 1 are not connected to the power supply potential VB supplied from the outside or other potentials, a surge voltage is applied to the terminals T5 and T6 at the power supply potential VB from the outside or other potentials. The same effects as those of the first embodiment can be obtained, such as noise caused by superimposing and the like is difficult to be placed.

Further, the level generation circuits 72 and 73 of the second modification shown in FIG. 5 have substantially the same configuration as the level generation circuits 70 and 71 of the first modification, but the connection destination of the resistors R3 and R4 is the same as that of the first modification. The difference is that the control power supply voltage Vcc2 is changed to the output potential VB1 of the surge protection circuit 20 composed of a varistor or the like. That is, in the second modification, the terminals T5 and T6 are connected to the output potential VB1 of the surge protection circuit 20 via the diodes D3 and D4 and the resistors R3 and R4, respectively. In the second modification, the output potential VB1 of the surge protection circuit 20 corresponds to a determination potential, and the surge protection circuit 20 corresponds to a potential generation unit.
Similarly to the first modification, when the level generation circuits 72 and 73 according to the second modification are used instead of the level generation circuits 60 and 61 according to the first embodiment, the vehicle-mounted sensor 1 needs to be assigned an identification ID in advance. In addition, the same effects as those of the first embodiment can be obtained, such as that noise is hardly placed on the terminals T5 and T6.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. The in-vehicle sensor 1A according to the second embodiment has substantially the same configuration as the in-vehicle sensor 1 according to the first embodiment, but the connection between the terminals T5 and T6, which are setting external terminals, and the microprocessor 10A is an embodiment. Different from 1. The microprocessor 10A includes input ports 10I1 and 10I2 that are digital input signal ports (I / O input ports) and output ports 10O1 and 10O2 that are digital output signal ports (I / O output ports).
Hereinafter, regarding the second embodiment, parts different from the first embodiment will be described, and description of the same parts as the first embodiment will be omitted.

Similarly to the first embodiment, the terminals T5 and T6 of the bus connection connector 40 are connected to any potential outside the in-vehicle sensor 1A and to the outside of the in-vehicle sensor 1A. This is an external terminal for setting to be in one of the second connection states (ground state) connected to the ground potential GND. In FIG. 6, the terminal T5 is connected to the ground potential GND by the setting path 140 (the line 141 indicated by the solid line and the nonexistent line 142 indicated by the broken line) of the connection path 100 (second connection state). The terminal T6 is in an open state (first connection state).
These two terminals T5 and T6 are connected to the cathode sides of diodes D5 and D6 for protection against surge noise and the like, as shown in FIG. It is connected to the input ports 10I1 and 10I2 of the microprocessor 10A. The input ports 10I1 and 10I2 connected to the anodes of the diodes D5 and D6 are connected to the output ports 10O1 and 10O2 of the microprocessor 10A through resistors R7 and R8, respectively. The diodes D5 and D6 and the resistors R7 and R8 constitute input generation circuits 80 and 81 connected to the terminals T5 and T6, the input ports 10I1 and 10I2, and the output ports 10O1 and 10O2.
The microprocessor 10A changes the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 between a high level and a low level when setting an identification ID at a predetermined timing such as when the power is turned on (output changing unit). Specifically, for example, when the input levels of the input signals SI1 and SI2 input to the input port 10I1 change according to changes in the high level and low level of the output signals SO1 and SO2, this input When it is determined that the terminal T5 connected to the port 10I1 is in an open state (first connection state), and the input levels of the input signals SI1 and SI2 input to the input port 10I1 are fixed at a low level and do not change The terminal T5 connected to the input port 10I1 is determined to be connected to the ground potential GND (second connection state) (response determination unit). The same applies to the terminal T6 connected to the input port 10I2 and the output port 10O2. That is, in the second embodiment, the input signals SI1 and SI2 (first input signals) when the connection state of the terminals T5 and T6 is the first connection state (open state) correspond to the changes in the output signals SO1 and SO2. On the other hand, since the input signals SI1 and SI2 (second input signals) when the connection state of the terminals T5 and T6 is the second connection state (ground state) do not change regardless of the output signals SO1 and SO2, this first The connection state of the terminals T5 and T6 is determined based on the difference in response between the first input signal and the second input signal.
Then, the identification ID of the in-vehicle sensor 1A is set according to the connection state of these terminals T5 and T6 (identifier setting unit). Since the second embodiment has two terminals T5 and T6 as setting external terminals as in the first embodiment, there are 2 ² = 4 combinations depending on the connection state of the two terminals T5 and T6. In addition, four types of identification IDs can be set.

Next, the operation at the time of setting the identification ID of the microprocessor 10A in the in-vehicle sensor 1A according to the second embodiment will be described with reference to the flowcharts of FIGS. FIG. 7 is a flowchart of the first half of the operation when setting the identification ID, and FIG. 8 is a flowchart of the second half. The microprocessor 10A executes the operation for setting the identification ID only once after the power is turned on.
First, in step S11 shown in FIG. 7, the output port 10O1 (output signal SO1) of the microprocessor 10A is set to a high level in order to start the determination of the connection state for the terminal T5. In the subsequent step S12, the microprocessor The input level of the input port 10I1 (input signal SI1) of 10A is read.

  Next, in step S13, it is determined whether or not the input level of the input port 10I1 read in step S12 is a high level. If the input level of the input port 10I1 is high, the determination in step S13 is Yes and the process proceeds to step S14. On the other hand, if the input level of the input port 10I1 is low level, No in step S13, and the process proceeds to step S18.

In step S14, the output port 10O1 (output signal SO1) is set to the low level to change the output port 10O1 (output signal SO1) from the high level to the low level. In the subsequent step S15, the input port 10I1 ( Read the input level of the input signal SI1).
In the subsequent step S16, it is determined whether or not the input level of the input port 10I1 read in step S15 is a low level. If the input level of the input port 10I1 is low level, Yes is made in step S16 and the process proceeds to step S17. In this case, since the input level of the input port 10I1 changes in synchronization with the change of the high level and low level of the output port 10O1 (output signal SO1), the terminal T5 connected to the input port 10I1 is It is determined that it is in the open state (first connection state), and the process proceeds to step S22 shown in FIG. If the answer is No in step S16, it is an abnormal case, so the process returns to step S11 and the determination of the connection state for the terminal T5 is performed again from the beginning.

Also, when the process proceeds from step S13 to step S18, as in step S14, the output port 10O1 (output signal SO1) is changed from the high level to the low level by setting the output port 10O1 (output signal SO1) to the low level. In step S19, the input level of the input port 10I1 (input signal SI1) is read.
In the subsequent step S20, it is determined whether or not the input level of the input port 10I1 read in step S19 is a low level. When the input level of the input port 10I1 is low level, Yes is made in step S20 and the process proceeds to step S21. In this case, since the input level of the input port 10I1 is fixed to the low level regardless of the change of the high level and low level of the output port 10O1, the terminal T5 connected to the input port 10I1 is connected to the ground potential GND. Is connected (second connection state), and the process proceeds to step S22 shown in FIG. Further, if No in step S20, it is an abnormal case, so as in the case of No in step S16, the process returns to step S11 and the determination of the connection state for the terminal T5 is performed again from the beginning. In these abnormal cases, error processing may be performed instead of returning to step S11.

  In step S22, the output port 10O2 (output signal SO2) of the microprocessor 10A is set to a high level in order to start the determination of the connection state for the terminal T6, and in the subsequent step S23, the input port 10I2 ( Read the input level of the input signal SI2).

  Next, in step S24, it is determined whether or not the input level of the input port 10I2 read in step S23 is a high level. If the input level of the input port 10I2 is high, the determination in step S24 is Yes and the process proceeds to step S25. On the other hand, when the input level of the input port 10I2 is low level, No is made in step S24, and the process proceeds to step S29.

In step S25, the output port 10O2 (output signal SO2) is set to the low level to change the output port 10O2 (output signal SO2) from the high level to the low level. In the subsequent step S26, the input port 10I2 ( Read the input level of the input signal SI2).
In the subsequent step S27, it is determined whether or not the input level of the input port 10I2 read in step S26 is a low level. If the input level of the input port 10I2 is low level, Yes is made in step S27 and the process proceeds to step S28. In this case, since the input level of the input port 10I2 changes in synchronization with the change of the high level and low level of the output port 10O2 (output signal SO2), the terminal T6 connected to the input port 10I2 is It judges that it is an open state (the 1st connection state), and progresses to Step S33. Further, if No in step S27, it is an abnormal case, so the process returns to step S22, and the determination of the connection state for the terminal T6 is performed again from the beginning.

Even when the process proceeds from step S24 to step S29, the output port 10O2 (output signal SO2) is changed from the high level to the low level by setting the output port 10O2 (output signal SO2) to the low level as in step S25. In step S30, the input level of the input port 10I2 (input signal SI2) is read.
In subsequent step S31, it is determined whether or not the input level of the input port 10I2 read in step S30 is a low level. If the input level of the input port 10I2 is low level, Yes in step S31, and the process proceeds to step S32. In this case, since the input level of the input port 10I2 is fixed to the low level regardless of the change of the high level and low level of the output port 10O2, the terminal T6 connected to the input port 10I2 is connected to the ground potential GND. Is connected (second connection state), and the process proceeds to step S33. If the answer is No in step S31, it is an abnormal case, so that the process returns to step S22 as in the case of No in step S27, and the determination of the connection state for the terminal T6 is performed again from the beginning. In these abnormal cases, error processing may be performed instead of returning to step S22.

In step S33, the identification ID of the in-vehicle sensor 1A is set to a code corresponding to the connection state of the two terminals T5 and T6, the set identification ID is stored in the memory, and the operation for setting the identification ID is completed.
In the second embodiment, the input generation circuits 80 and 81 and the microprocessor 10A executing steps S11 to S21 and steps S22 to S32 correspond to a determination unit. Of these, the microprocessor 10A executing steps S11, S14, and S18 and steps S22, S25, and S29 corresponds to an output changing unit, and steps S12 to S13, S15 to S17, S19 to S21, and step S23. The microprocessor 10A that executes S24, S26 to S28, and S30 to S32 corresponds to the response determination unit. Further, the microprocessor 10A executing step S33 corresponds to an identifier setting unit.

  As in the first embodiment, the in-vehicle sensor 1A according to the second embodiment is connected to four CAN sensors 1A of the same specification on the CAN bus using the connection paths 100, 200, 300, and 400. Four different identification IDs can be set by changing the connection states of the terminals T5 and T6 of each in-vehicle sensor 1A to different states (see FIG. 2).

As described above, in the in-vehicle sensor 1A of the second embodiment, the connection state of the terminals T5 and T6 is set to the first connection state (open state) or the second connection state (grounding) by the input generation circuits 80 and 81. State, the input signals SI1 and SI2 (first input signal and second input signal) having different responses to changes in the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 of the microprocessor 10A are generated. Then, the data is input to the input ports 10I1 and 10I2 of the microprocessor 10A. Then, the output change section (steps S11, S14, S18, S22, S25, and S29) in the microprocessor 10A changes the output signals SO1 and SO2 output from the output ports 10O1 and 10O2, and the input determination section in the microprocessor 10A. (Steps S12 to S13, S15 to S17, S19 to S21, S23 to S24, S26 to S28, S30 to S32) Responses of the input signals SI1 and SI2 input to the input port 10I1 to changes in the output signals SO1 and SO2 Is used to determine the connection state of the terminals T5 and T6. Specifically, when the input level of the input signal SI1 input to the input port 10I1 changes (first input signal) according to changes in the high level and low level of the output signal SO1 output from the output port 10O1. Determines that the terminal T5 connected to the input port 10I1 is in an open state (first connection state), and the input level of the input signal SI1 input to the input port 10I1 is fixed at a low level and does not change. For (second input signal), it is determined that the terminal T5 connected to the input port 10I1 is connected to the ground potential GND (second connection state). The same applies to the terminal T6.
Thereby, the connection state of the terminals T5 and T6 is appropriately determined according to the response of the input signals SI1 and SI2 input to the input ports 10I1 and 10I2 with respect to changes in the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 of the microprocessor 10A. Can be determined.

Further, in the in-vehicle sensor 1A of the second embodiment, the input generation circuits 80 and 81 connect the input ports 10I1 and 10I2 of the microprocessor 10A to the terminals T5 and T6 through the diodes D5 and D6, and the resistor R7. , R8 to output ports 10O1, 10O2.
Thereby, when the connection state of the terminals T5 and T6 is the first connection state (open state), the input signals SI1 and SI2 change in synchronization with the change of the output signals SO1 and SO2 output from the output ports 10O1 and 10O2. On the other hand, when the connection state of the terminals T5 and T6 is the second connection state (ground state), the input signals SI1 and SI2 do not change in synchronization with the changes of the output signals SO1 and SO2, and are fixed at the low level. The
Therefore, in this in-vehicle sensor 1A, the input generation circuits 80 and 81 can be simply configured, and the connection state of the terminals T5 and T6 can be appropriately determined.

  In addition, since the vehicle-mounted sensor 1A of the second embodiment has the same operational effects as those of the first embodiment, the vehicle-mounted sensor system 2 of FIG. 2 is replaced with the vehicle-mounted sensor 1A instead of the vehicle-mounted sensor 1 of the first embodiment. You may apply to. Thus, by simply connecting the bus connection connectors 40 of the four in-vehicle sensors 1A to the sensor connection connectors 110 to 410 of the connection paths 100 to 400, different identification IDs can be set for the four in-vehicle sensors 1A. The in-vehicle sensor system 2 that does not need to be assigned is obtained.

(Modification 3)
Next, a modified embodiment in which the configuration of the input generation circuits 80 and 81 of the second embodiment is changed will be described with reference to FIG.
The input generation circuits 80 and 81 of the second embodiment are similar in circuit configuration to the level generation circuits 60 and 61 of the first embodiment, as can be seen by comparing FIG. 6 with FIG. Specifically, in the level generation circuits 60 and 61 of the first embodiment, the resistors R1 and R2 are connected to the constant control power supply voltage Vcc2, whereas in the input generation circuits 80 and 81 of the second embodiment. The resistors R7 and R8 are connected to the output ports 10O1 and 10O2 of the microprocessor 10A, and output signals SO1 and SO2 output from the output ports 10O1 and 10O2 are changed, but the other configurations are the same. is there.
On the other hand, the input generation circuits 90 and 91 of the third modification shown in FIG. 9 are similar in circuit configuration to the level generation circuits 70 and 71 (see FIG. 4) of the first modification.

  In the third modification, the terminals T5 and T6 are connected to the bases of the transistors Q3 and Q4, respectively, and to the cathode sides of the protective diodes D7 and D8. The anodes of the diodes D7 and D8 are connected to the control power supply voltage Vcc2 (= + 3.3V) via resistors R9 and R10, respectively. The emitters of the transistors Q3 and Q4 are grounded to the ground potential GND, and the collectors of the transistors Q3 and Q4 are connected to the output ports 10O1 and 10O2 of the microprocessor 10A via resistors R11 and R12, respectively. It is connected to the input ports 10I1 and 10I2 of the processor 10A. These diodes D7 and D8, resistors R9 and R10, transistors Q3 and Q4, and resistors R11 and R12 constitute input generation circuits 90 and 91, and the microprocessor 10A outputs from output ports 10O1 and 10O2. The output signals SO1 and SO2 to be changed are changed between a high level and a low level.

Therefore, in the level generation circuits 70 and 71 of the first modification, the resistors R5 and R6 are connected to the constant control power supply voltage Vcc2, whereas in the input generation circuits 90 and 91 of the third modification, the resistors Although the devices R11 and R12 are connected to the output ports 10O1 and 10O2 of the microprocessor 10A and the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 are changed, the other configurations are the same.
In the third modification, when the terminals T5 and T6 are opened (first connection state), the bases of the transistors Q3 and Q4 become the control power supply voltage Vcc2 via the diodes D7 and D8 and the resistors R9 and R10. Since they are connected, the transistors Q3 and Q4 are turned on. Therefore, even if the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 are changed, the input ports 10I1 and 10I2 connected to the collectors of the transistors Q3 and Q4 are not affected by the change of the output signals SO1 and SO2. The input levels of the input signals SI1 and SI2 that are input are always low. On the other hand, when terminals T5 and T6 are connected to ground potential GND (second connection state), transistors Q3 and Q4 are turned off because the bases of transistors Q3 and Q4 are connected to ground potential GND. Therefore, when the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 are changed, the input signals input to the input ports 10I1 and 10I2 connected through the resistors R11 and R12 in synchronization with the change. SI1 and SI2 also change.
As a result, the in-vehicle sensor 1A of the second embodiment can use the input generation circuits 90 and 91 of the modification 3 instead of the input generation circuits 80 and 81, and has the same operational effects.

In the above, the present invention has been described with reference to Embodiments 1 and 2 and Modifications 1 to 3. However, the present invention is not limited to the above-described embodiments and modifications, and is within the scope not departing from the gist thereof. Needless to say, the present invention can be applied with appropriate changes.
For example, in the embodiment and the modification, two terminals T5 and T6 are provided as setting external terminals, and 2 ² = 4 different identification IDs can be set. However, the number of setting external terminals can be changed as appropriate according to the number of in-vehicle sensors 1 connected to the communication bus. When n setting external terminals are provided, 2 ⁿ identification IDs are provided. It is possible to set.
In the embodiment and the modification, the in-vehicle sensor 1 is a sensor connected to the CAN bus. However, the present invention is applied to an in-vehicle sensor connected to a communication bus other than the CAN bus such as a LIN bus. Also good.

In the first embodiment and the first modification, the control power supply voltage Vcc2 for driving the microprocessor 10 generated by the stabilized power supply circuit 30 is used as a determination potential. In the second modification, the output potential of the surge protection circuit 20 is used. VB1 was used as a discrimination potential. However, the discrimination potential may be generated by a separate dedicated circuit.
The input ports 10I1 and 10I2 in the first embodiment and the first and second modifications use digital input signal ports (I / O input ports), but use analog input signal ports (A / D input ports). May be. Similarly, in Embodiment 2 and Modification 3, analog output signal ports (D / A output ports) are used as output ports 10O1 and 10O2 instead of digital output signal ports (I / O output ports). Alternatively, A / D input ports may be used as the input ports 10I1 and 10I2.

  Furthermore, in the second embodiment and the third modification, the input signals are output from the output ports 10O1 and 10O2 by using the input generation circuits 80 and 81 and the input generation circuits 90 and 91, respectively. The connection state of the terminals T5 and T6 was determined using the responses of the input signals SI1 and SI2 input to 10I1 and 10I2. However, as described above, the input generation circuits 80 and 81 of the second embodiment are the level generation circuits 60 and 61 of the first embodiment, and the input generation circuits 90 and 91 of the third modification are the level generation circuits of the first modification. 70 and 71. When the output signals SO1 and SO2 output from the output ports 10O1 and 10O2 of the microprocessor 10A are fixed at a high level, the input generation circuits 80 and 81 and the input generation circuits 90 and 91 are respectively leveled. The operation is the same as that of the generation circuits 60 and 61 and the level generation circuits 70 and 71. Therefore, by fixing the output signals SO1 and SO2 to the high level, the input generation circuits 80 and 81 of the second embodiment and the input generation circuits 90 and 91 of the third modification can be used as the level generation circuit.

VE Vehicle 1, 1A In-vehicle sensor 2 In-vehicle sensor system 10, 10A Microprocessor 10I1, 10I2 Input port 10O1, 10O2 Output port R1, R2, R3, R4, R7, R8 Resistor 20 Surge protection circuit 30 Stabilized power supply circuit (potential Generator)
40 Bus connector T1 terminal (power supply terminal)
T2 terminal (ground terminal)
T3 terminal (communication external terminal)
T4 terminal (communication external terminal)
T5 terminal (external terminal for setting)
T6 terminal (external terminal for setting)
60, 61, 70, 71, 72, 73 Level generating circuits 80, 81, 90, 91 Input generating circuit VB Power supply potential GND Ground potential Vcc2 Control power supply voltage (discriminating potential)
CAN CAN bus (communication bus)
CANH, CANL Communication line 100, 200, 300, 400 Connection path 110, 210, 310, 410 Sensor connection connector 130 Communication connection path 140, 240, 340, 440 Setting path S1-S4, S5-S7 Level discriminating section (discriminating section )
S11, S14, S18, S22, S25, S29 Output changing part (discriminating part)
S12 to S13, S15 to S17, S19 to S21, S23 to S24, S26 to S28, S30 to S32 Response discrimination unit (discrimination unit)
S8, S33 identifier setting part

Claims (6)

An in-vehicle sensor mounted on a vehicle and connected to a communication bus built on the vehicle,
One or more communication external terminals connected to a communication line through which communication data flows in the communication bus, and
Each is
A first connection state that is not connected to any potential outside the in-vehicle sensor; and
Including one or a plurality of setting external terminals to be connected to any one of the second connection states connected to the ground potential outside the vehicle-mounted sensor,
A bus connector used for connection to the communication bus;
For each of the one or more setting external terminals, a determination unit that determines whether the connection state is the first connection state or the second connection state;
An in-vehicle sensor comprising: an identifier setting unit configured to set an identifier of the in-vehicle sensor used in the communication bus according to the determined connection state of the one or more external setting terminals. The in-vehicle sensor according to claim 1,
A microprocessor having an input signal port through which an input signal is input;
The discrimination unit
A level generation circuit that connects to the setting external terminal and the input signal port, and generates the input signal having different voltage levels according to the connection state of the setting external terminal;
A level determining unit that determines whether the connection state of the setting external terminal is the first connection state or the second connection state based on the voltage level of the input signal input to the input signal port An in-vehicle sensor. The in-vehicle sensor according to claim 2,
A potential generator for generating a constant discrimination potential;
The level generation circuit includes:
The external terminal for setting is connected to the discrimination potential via a resistor,
A vehicle-mounted sensor that is a circuit that generates the input signal using the potential of the setting external terminal. The in-vehicle sensor according to claim 1,
A microprocessor having an input signal port for inputting an input signal and an output signal port for outputting an output signal;
The discrimination unit
A first input signal that is connected to the setting external terminal, the input signal port, and the output signal port, and is the input signal when the connection state of the setting external terminal is the first connection state; and At least one of the second input signals that are the input signals when the connection state is the second connection state changes according to a change in the output signal, and the first input signal and the first input signal An input generation circuit for generating the input signal different from two input signals;
An output changing unit that changes an output signal output from the output signal port;
Whether the connection state of the setting external terminal is the first connection state or the second connection state by using the response of the input signal input to the input signal port to the change of the output signal A vehicle-mounted sensor having a response determination unit for determining The in-vehicle sensor according to claim 4,
The input generation circuit includes:
A vehicle-mounted sensor that is a circuit that connects the input signal port to the setting external terminal and also connects the output signal port via a resistor. A vehicle-mounted sensor system comprising a plurality of vehicle-mounted sensors according to any one of claims 1 to 5 and the communication bus to which these are connected,
For each of the plurality of in-vehicle sensors, including a sensor connection connector that fits into the bus connection connector of the in-vehicle sensor, including a plurality of connection paths that connect the in-vehicle sensor to the communication bus,
The plurality of connection paths are
A communication connection path for connecting the one or more communication external terminals of the bus connection connector to the communication line of the communication bus;
The setting external terminals of the bus connection connector are not connected to any potential or are connected to the ground potential, and the connection states of the setting external terminals are changed to the first connection state and the second connection, respectively. One or more setting paths defined in any of the states,
One or a plurality of the setting paths are in-vehicle in which the connection state or the combination of the setting external terminals determined by itself is different among the connection paths, and the identifiers are different from each other for all the in-vehicle sensors. Sensor system.

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